SPRINGFIELD, Mass.-- Recent forensic tests have linked evidence found near the body of a 10-year-old girl killed more than 18 years ago to a man who died in 2003, authorities said Tuesday. They also announced a $15,000 reward for information leading to the capture and conviction of the girl's killer or killers.

Hampden District Attorney Mark Mastroianni said David Edmund Pouliot of Springfield is not considered a suspect in the killing of Holly Piirainen, but authorities are looking for more information about him. Mastroianni declined to release details about the evidence but said it was found "in close proximity" to the girl's body.

He said it was possible that others associated with Pouliot may have a role in the child’s death.

Holly was last seen on Aug. 5, 1993, near her grandparents' summer cottage in Sturbridge as she and her younger brother went to see a litter of puppies down the road. Only her brother returned. Hunters found her body two months later about five miles away in a wooded area of Brimfield.

Mastroianni also said the new forensic testing did not turn up anything linking Holly's killing to the still-unsolved death of 16-year-old Molly Bish, whose body was found in Palmer in 2003, three years after she was last seen at her lifeguard job in Warren. Palmer and Warren are close to Sturbridge and Brimfield.

"This is a significant new lead," Mastroianni said at a news conference in Springfield, where photos of Pouliot were shown and the reward was announced. "We want information about Mr. Pouliot. ... We're hoping that seeing the picture will trigger someone's memory.

"The nature of the item suggests that either Mr. Pouliot or people associated with him were in this immediate area at a time relevant to Holly's disappearance and the finding of her remains."

Members of Holly's family, including her grandmother, Maureen Lemieux, who owned the cottage in Sturbridge, attended the news conference. Lemieux said the family has been on a "rollercoaster ride" since her granddaughter's death, because there have been several people of interest named in the investigation over the years.

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"I'm cautiously optimistic and I'm waiting for further results," Lemieux said. "I would like to see some result in my lifetime."

Lemieux added: “I’m 18 years older than I was then. I would like to see some results in my lifetime. … It would be wonderful. It would be the hopes of our dreams.’’

Lemieux said her family has did not know Pouliot and has never heard of him.

Pouliot was an avid fisherman and outdoorsman who served in the Coast Guard during the Vietnam War era, according to an obituary in The Republican of Springfield. He was 49 when he died at his mother's home in Springfield. He had worked for Springfield's parks department and a state juvenile detention center in Westfield.

Investigators urged anyone with information about Pouliot or the case to call their tip line at (413) 505-5933 or text a tip to CRIMES (274637) and begin with the word "Solve."

Msnbc.com staff contributed to this report from The Associated Press.